Programmable Logic Controller

Learn PLC Programming without spending a dime!

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plc basics programmable logic controller

I have been writing PLC programs for over 20 years. I often get asked what the best way to learn PLC programming is. Programming in the way I was taught in college was with the Motorola 6809. (Yes, I know that I am dating myself) This was microprocessor programming, but it was the best way … Read more

How to Implement Omron PLC Host Link Protocol

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The hostlink communication protocol is a method developed by Omron for communication to PLCs and other equipment. This ASCII-based protocol is used over RS232 or RS422/RS485. It is a many-to-one implementation, meaning you can communicate with up to 32 devices back to a master. (1: N) This communication on the industrial floor can control PLCs, Temperature … Read more

How to make a Start Stop Jog circuit in a PLC

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Looking at a stop-start jog circuit in the PLC will help us understand the differences in hard-wiring the circuit and programming. Basic Start Stop Circuit Let’s start with the primary start-stop circuit. Here is what it looks like hard-wired. (Physical switches wired to outputs devices, such as motor contactors and relays.) When the start pushbutton … Read more

Now You Can Have Robust Data Logging for Free – Part 12

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Now You Can Have Robust Data Logging for Free – Part 12 HTML and Scripting Languages  We have the following accomplished: PLC program Visual Basic Program Data collected in a Database IIS web service established ASP Script Written Let’s take a closer look at the ASP Script ( AccRL.asp) that was written in part 11: … Read more

Now You Can Have Robust Data Logging for Free – Part 11

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Now You Can Have Robust Data Logging for Free – Part 11 HTML and Scripting Languages  We have the following accomplished: PLC program Visual Basic Program Data collected in a Database IIS web service established The IIS web service machine must have the Microsoft Access Database Engine 2010 installed. The following link can obtain this: … Read more

Now You Can Have Robust Data Logging for Free – Part 10

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Now You Can Have Robust Data Logging for Free – Part 10 Computer Web Server (IIS)  We have come a long way. The PLC program has been written. The primary visual program has been reported. Information is now being collected from the Do-more PLC via Modbus TCP and stored in a database using visual basic. … Read more